Joey is an expert political pollster who is frequently called upon by President Josiah Bartlet's senior staff to administer national polls and interpret polling data. Joey is a native of California and attended UCLA and Stanford, though the degrees she received from each are unknown. Since she is deaf (as is Matlin in real life), she is usually accompanied by her interpreter, Kenny Thurman (portrayed by Bill O'Brien).

Joey once ran the campaign of Californian Democratic candidate for Congress Bill O'Dwyer until the President dismissed O'Dwyer as an "empty shirt" and suggested that Joey find another, better candidate to challenge the conservative Republican currently holding the seat. She also worked with and dated fellow pollster Al Kiefer (John de Lancie); Josh and Toby could not stand him and were won over by Joey largely because she was able to prove him wrong on a flag-burning issue.

In the second season of the show, Joey was brought in by then Deputy White House Chief of Staff Josh Lyman to do initial polling on potential public reaction to President Bartlet's disclosure that he had multiple sclerosis. She was the 21st person to learn of the President's disease. She continued working intermittently for the Bartlet administration, most notably before several of his State of the Union speeches. In the fifth season, when Josh wants to start a relationship with Joey she walks into the West Wing and we find out she is pregnant.

Following Congressman Matt Santos's decision to run for president, she worked as a consultant for the campaign, both before and after he was the Democratic nominee for president.

Late in the first season it became clear that former Deputy White House Chief of Staff Josh Lyman was attracted to Joey. Josh was discouraged when he got wind of Joey's brief fling with Al Kiefer.

In the second season Joey suggested that Josh pursue a relationship with his assistant, Donnatella Moss, responding to Moss's attempts at misdirection in advocating a relationship between her boss and Joey Lucas. The flirtation between Joey and Josh was one of the series' subplots.